Combined stoker and furnace



Jan. 28, 1947. Q H, @Usl-UNG 2,414,802

l COMBINED STOKER AND FURNACE Filed June 22, 1944 4 sheets-sheet 1 E. f/@n IN V EN TOR. George H. Cus/Jing Jamv 28, 1947. G. H. cusHlNG2,414,802

COMBINED STOKER AND FURNACE Filed June 22, 1944 sheets-sheet s Fig. .3

. INVENTOR. Geo/je H. Cushing G. H. cusHlNG 2,414,802

COMBINED STOKER AND FURNACE Filed June 22. 1944 4 Sheets-Sheet 4 Jan..28, 1947.

n i a N C M l. Bmw/ 0 Wd fev7 l @Q l J V.. R. mm,|\ B lww @EN Qu ,y .lnu \w\\ @l M M-J.. Nm all" ""IIHHI, I...... I |$v fl Y f2 m A@ fPatented Jan. 28, 1947 UNITED STATES PATENT OFFICE commun s'roinin ANDFURNACE George n. Cushing, chicago, 111. Application .l une 22, 1944,Serial No. 541,545

(o1. 11o-s2) 9 Claims. l

This invention relates to a method of and apparatus for burning hardfuel and part of the subject matter thereof has been divided from mypending application for patent on an improvement in Coal stokers andcontrol thereof and the like, filed February 6, 1943, under Serial No.474,937, and is a continuation in part thereof.

One of the objects of this invention is the provision of a novel methodfor burning hard fuel, such as the various kinds of coal, coke, etc.,whereby all of the combustibles in fuel may be entirely consumed,leaving only a residue of ne ash.

Another object is the provision of a method of burning hard fuel whereinfresh charges of the fuel are charged upon a cleared section of thegrate and contiguous with a previous charge which has become ignited.

Another object is the provision of a method of burning hard fuel whichconsists in controlling the amount of the charges of fuel, the frequencyof introducing the charges upon the grate, coordinatedwith damper meansto regulate the draft in accordance with the frequency of charging thefurnace, whereby a substantially constant temperature may be maintainedin the space or spaces heated by the furnace, regardless of the outsidetemperature.

Another object of this invention is to provide a side feed stoker foruse in connection With a furnace or other heating apparatus for burninghard fuel in measured quantities concurrently in predetermined stages ofcombustion.

Another object is to provide a Stoker with automatic feed and automaticash remover.

Another object is to provide a furnace capable of burning a greatvariety of sizes of solid fuel, either separately or mixed.

Another object is to provide a stoker which will free its operator fromany manual attendance upon the furnace.

.Another object is to provide a simple and compartly in verticallongitudinal section taken substantially along the line 2-1-2 of Fig. l,with roller 15a shown in dotted lines to indicate its location;

Fig. 3 is an end elevation looking in the direction of the arrow 3 inFig. 2;

Fig. Il is a perspective view of fragments of the reservoir, re box andashv conveyor, and illustrating atrack for a certain trap doorassociated with the grate;

Fig. 5 is a front elevation of a control box seen in Fig. 2; A

Fig. 6 is a vertical cross section taken on the line E- of Fig. 5;

Fig. '7 is a horizontal section l'-'l lof Fig. 5;

Fig. 8 is a vertical section taken `on. the line 8-8 of Fig. '7;

Fig. 9 is a vertical section through fragments of a smoke pipe,illustrating the damper;

Fig. 10 is a plan of the damper seen in Fig. 9 with the smoke pipe shownin section;

Fig. l1 is an under plan of a fragment of one of the grate segments; andY Fig. 12 is a wiring diagram of a time switch used for controlling thestarting and stopping of the notor which operates the stoker.

Referring to said drawings, which are somewhat schematic and illustrateoneV embodiment of the invention, the reference character Il] designatesthe casing of a furnace or other solid fuel burning heating apparatus,in the lower end Vof Which is a low fire-brick wall II surrounded by asheet metal retaining wall I Ia.

Mounted upon a base plate l2, which extends within and without thecasing I0, is a base I3 upon which is secured a post I4 having anannular shoulder I5 upon which rests a beveled gear Wheel I6 whichcarries a grate composed of grate sections I1 that are desirably ofsegmental form and ride on a circular track I Ib carried by theretaining wall II. Also mounted on the upper end taken on the 'line i ofthe post I4 is an air dome I8. The grate and rire-brick wall Ila providea lire-box: in which the fuel is consumed. The beveled gear wheel andgrate are intermittently rotated in timed relation to the feeding offuel upon Ithe grate and the means for rotating the grate may comprisethe beveled gear Wheel I6 which meshes with a beveled pinion 29 mountedupon one end of a shaft 2| journaled in suitable bearings andintermittently rotated from the main drive shaft 30 of the apparatus bysuitable gearing, as will be presently described.

Disposed at one side of the furnace is a fuel delivery conduit orreservoir 22 which is located therefrom toreceive Ibetween said sidewalls a reciprocating ram or plunger 2B which functions tointermittently feed solid fuelinto the fire-box and upon the grate andin an approximately radial direction with respect to the axis of thegrate. l

The bottom Wall 21 of the reservoir projects over the edge portion ofthe grate and guides the Afuel thereto. The top wall of the reservoirhas an opening 29 therein located above and forward of the ram, Fuelentering said opening falls upon' and in front of the ram where it liesuntil the ram is retracted, whereupon the fuel lying upon the ram fallsinto the reservoir in front of the front face of the' ram, This space inthe reservoir is calculated to hold a measured quantity of fuelsufficientV for one charge besides a wall of fuel which always remainsin the throat.

Any form of hopper or fuel feed may be employed to deliver fuel into thereservoir and the one illustrated will be hereinafter described.

Journaled in suitable bearing brackets ila mounted on the base plate isthe main drive shaft 3B, here shown in the form of a crank shaft ofwhich the crank 3l is connected to one end of connecting rod 32, theother end of which is connected to the ram 26 by a wrist pin 33 securedin the side walls of the ram.

Mounted on a motor base 34, which rests on andis secured to the baseplate `I2, is a motor 35, desirab-ly in the form of anA electric motor,which comprises the prime mover for the apparatus. Associated with themotor is speed reducing gearing 36 which couples the motor shaft withthe main drive shaft 39 and rotates the same through one or morecomplete revolutions during each cycle of operation of the Stoker.Mounted adjacent the speed reducing gearing is a circuit breaker or timeswitch 3l which breaks the circuit for the motor at the completion ofeach cycle of op eration.

The circuit breaker or time switch maybe of the common and well knowntime switches controlled by a rotating shaft to break the circuit at theconclusion of a cycle of operation,

In Fig. 12, such a time' switch 37 is shown, having a magnet 31aconnected tothe control means 40, 45, by lines 43, 65a. The associatedarmature s'lb is connected to a movableA switch contact piece 31o by alink 31d and makes contact with a stationary `contact'piece 31e wheneverthe magnet is energized'as a result of one of the contact points 4|closing the circuit through the magnet` When the circuit through theconductors 3U, 31p to the motor 35 is closed by the contacts 31e and31e, the motor is started. A latch 31h has a finger that prevents themovable contact 37e from breaking con-tact with the stationary contact31e when the magnet 31a is rie-energized .as a result of the contact 4|running on? the contacts 45. TheV latch 31h is connected to a releaselever 3h by a link, and the main drive shaft so has a pin or stud 31jthereon, which engages the lever 31a when the shaft has made onecomplete revolution, thereby releasing the movable contact 31e from thelatch and permitting it to be swung out of contact with the stationarycontact 37e, therebyv Lil.

y4 opening the circuit through the conductors 31j. 31g and stopping themotor.

The control means for controlling the frequency of charging the furnaceand for controlling the damper is best seen in Figs. 5 to lo inclusive.This control means may be installed at any convenient place in thebuilding heated by the furnace. In general, i-t comprises a. cabinet 33in which is mounted a motor 3a, such as a clock works, upon the maindrive shaft 3sat of which is removably mounted a time disc lll composedof non-conducting material and having concentric rows of contact points[l5 secured therein with their ends flush with the side faces or" thedisc. The contact points are spaced equidistantly in each row 'but thenumber of contact points in each row increases progressively outwardfrom the center of the disc so that with a constant rate of speed of thedisc a more or less number of contact pieces will pass a given pointduring each hour or day.

Sl-idably guided in a vertical guideway ft2 secured to a side wall ofthe cabinet is a vertically movable contact carrying member i4 formedwith .a forked arm l5 straddling the disc and contain-y ing twoelectrical conductors which `are provided with inturned lcontact fingersliladapted to make Contact with the contact points il of any row'. Meansare provided for raising and lowering the contact carrying member .14 soas to position the lingers to make Contact with any given 'row ofcontact points, depending upon outside temperature, grade of coal, etc.The means here shown for this. purpose comprise an upright rack barlliSwhich extends up from the forked arm t5 and has rack teeth on one edgethat mesh with a pinion i9 fast on a shaft or a spindle 56 that extendsout through and is secured to a dial Eil which cooperates with a Vernier52 secured in thefront Wall 38. A suitable bearing bracket 53 supportsthe shaft and a knob is fastened on its outer extremityv whereby itmaybe rotated. Rotation of the shaft will raise or lower the con'- tactcarrying member it through the instrumentality of the pinion and rackbar.

The contact carrying member ill also Vcoinbrols the damper 55 which iscontained in the smoke pipe 56 of the furnace. lThe damper consists of,-two substantially semi-circular damper plates 5l carried `by twoparallel rods 58 which are rotatably mounted in a split ring 5e, clampedupon the two adjacent ends of two smoke pipe sections. On `one end ofthe rods 5S are formed crank arms 68 that cross each other and inclineupwardly away from the damper plates when the latter occupy a horizontalposition. Means are employed for holding the damper plates in anyposition of adjustment and, as shown, said means comprises a weightedbody 6I which rests upon the upper extremities of the crank arms and issuspended by a cable or other flexable element 62 passing over sheaves63, $4 and extending to the contact carrying member 415 where the cableis secured to Said member. When the Contact carrying member is loweredto increase the firing frequency it raises the weighted body 6i, penmitting the damper plates to swing down under the force of gravity,thereby enlarging the pasM sageway between the damper plates and thesmoke pipe. Y

In the operation of the control means just described, when the forkedarm 5 is set to make contact with the outermost row of contacts, theweighted member 6i has been raised to the limit of its upward movement,thereby holding the damper plates in their fully open position. In thisposition of the contact carrying member the contact lingers are arrangedto make contact with the contact points in the outermost row containingthe greatest number of contacts; and as a result, the circuit to thecircuit breaker or time switch is closed frequently, thereby causingfrequent charging of the furnace. In milder weather the contact carryingmember is raised more or less by rotating the knob 54 in a clockwise-direction thereby bringing .the forked contact carrying arm 45 into aposition in which .the contact fingers contact with `one or another ofthe inner rows of contact points, and simultaneously the weighted body6I is lowered thereby swinging the damper plates into `a more or lesshorizontal position.

The electrical conductors 65a lead from the control cabinet through thecircuit breaker or time switch 31 and are suitably connected to thehouse current. It is to be understood that, as the disc slowly revolveswith the contact carrying member set to make contact between the contactlingers and the contact points of any row, as each contact pointcontacts the fingers, it closes the circuit to the circuit breaker ortime switch, thereby closing the circuit to the motor and setting it inmotion. The circuit breaker or time switch is set to permit the motor torun for a suicient length of time to rotate the drive shaft 30 throughone or more complete revolutions of 360 degrees and then break the.circuit and stop the motor.

It is to be understood that during each cycle of operation `a measuredcharge of fuel is charged into the fire box and upon .the grate, whichcharge is deposited upon the grate contiguous with the previous chargeof fuel which has al ready been ignited- Each charge of fuel assumes a"pie slice form upon the grate and is ignited from the burningpreviously deposited charge. The grate and the fuel thereon remainstationary until the ram is being retracted, whereupon the grate isgiven a partial rotation whereby to present a vacant space on the grateto receive a subsequent charge to be deposited contiguous with the lastcharge. The means for intermittently rotating the grate will now bedescribed.

An accepted practice when coal is fired by hand has been for years tomove the live coal to one side and re the green coal on ,the vacatedspace. In laddition to the standard practice, I have provided clearancespace between the bottom of the partition and grate to permit smallamounts of coked coal to pass beneath the partition to serve askindling. Finally the green coal impinges against the incandescent coalin the previously deposited charge and is ignited.

Mounted upon the shaft 30 is a mutilated gear wheel B which is arrangedto mesh with a gear wheel 66 mounted upon a shaft 61 journaled in thebearing brackets Ma. Mounted upon shaft 61 is a beveled pinion 68 whichmeshes with a beveled pinion B9 mounted on the shaft 2|. The

mutilated gear wheel 65 has gear teeth upon 186 degrees of 4its face andis so related to the gear wheel 66 that when the main or crank shaft 30begins its'cycle of rotation `and begins to project the ram 2B, the gearwheel 66, shaft 2| and grate will remain idle, and that when the crankbegins to retract the ram, the first tooth of the mutilated gear wheelmeshes with the gear wheel 66 and rotates it and therewith rotates thebeveled pinions 68, 69, shaft 2|7 pinion 20 and gear wheel I E, therebyrotating the grate through a Rigidly secured to the side wall 24 of thereservoir is a partition or sweep 10 which extends radially over thegrate to the air dome i8. The partition 10 extends down to the grate andit functions to sweep the ashes from the grate as lthey encounter thepartition.

One of the grate segments is provided with a swingable trap door 1llocated in a cutout portion of a grate section. The trap door has aroller 12 (see Fig. 4) which projects in a radial direction with respectto the :axis cf the g-rate and runs upon the annular track l Ib. Thetrack is offset downwardly as at 13 to permit the trap door to swingdown and allow clinkers, slate and other unconsumed pieces to dischargefrom the grate.

Suitable fuel feed and lash removal apparatus are provided. one form ofwhich is shown for the .purposes of illustration.

Extending from a suitable fuel bin (not shown) is an inclined conveyor15 which conveys fuel to the reservoir and discharges itv through theopening 29 thereof. A cover or closure 16 is provided upon the reservoirabove the opening 2S. Any suitable driving means may be provided for theconveyor 15 and it is here shown as comprising a sprocket wheel 11 onthe shaft 2l, `a sprocket wheel 19 on the shaft of the upper roller 15aover which the conveyor is trained, and a sprocket chain 18 .trainedover said sprocket wheels.

The ash removal means, as shown, comprises a conveyor belt trainedaround rollers 8l, 82, 83 carried by suitable brackets. The conveyorbelt 80 is disposed below and at one side of the partition or sweep 10,as shown in Fig. Land a hopper 80a is provided below the grate forguiding the ashes to the conveyor belt. ISuitable means are provided fordriving the conveyor belt 80 and, as shown, said means comprise a Ibelt85 trained around a sheave 35 on the main crank shaft and a sheave 81 onIthe shaft of the roller 83.

Below the discharge end of the conveyor belt B is a transverselyextending conveyor beltl 84 which carries the ashes away from thefurnace. Driving means are provided for the conveyor belt 84 and, asshown, said means comprise a gear wheel 88 upon the shaft 2l whichmeshes with a pinion 89 on the shaft of the roller 90 over which theconveyor belt 84 is trained,

In the operation of the combined stoker and furnace, fuel is deliveredinto the fuel delivery conduit and the control means is set inaccordance with the outside temperature and the switch for the electriccircuit is closed.

. When one of the contacts 4l of the. control mechanism closes thecircuit through the conductors 45, 65a, the circuit is then closedthrough the time switch and through the motor which drives the maincrank shaft 3B through one complete rotation and then is stopped by thetime switch. During the first half revolution of the crank shaft thegrate is stationary and the plunger is moved toward the grate, therebydepositing a` charge of the fuel thereon. During the thereon in front ofthe discharge opening of the fuel feeding conduit.

The present method of burning solid fuels of any known but widelyvariable chemical composition and attendant variables comprises thesegregation of a predetermined quantity of solid fuel, measured byvolume, successively feeding charges of that solid fuel radially upon acleared section of a circular and perforated grate; igniting each freshcharge of solid fuel by the application `ofheat and air from the bottom,top and side of the fuel; rot-ating the grate at predetermined intervalsto the end that the coal, without being disturbed, may burn in a seriesof stages until combustion is complete; timing the movements of thegrate so that the coal will be consumed while the grate is making onecomplete revolution; regulating the timing of the grate movements topermit the use, at will, of the slowest and fastest burning solid fuelsor those havn ing a wide range of volatile content; providing automaticdraft regulation to supply the quantity of air needed by fuelbeds ofvarying thickness and burned in different time periods; .and removingthe ash, automatically, to close the grate to permit the free play ofair upon the fuel to be burned.

The electrical controlmeans for the motor and for the damper is set inaccordance with the outside temperature and the character of fuel used.

The fuel on the grate continues to burn until each charge has beenconsumed, leaving only a residue of ashes which encounter the partitionor sweep and are swept from the grate, leaving a clear space for a freshcharge.

Having thus described my invention, it is obviousI that variousimmaterial modifications may be made in the same without departing fromthe spirit ofY my invention; hence, I do not wish to be understood aslimiting myself to the exact aform, construction, arrangement andcombination of parts herein shown and described, or uses mentioned,

What I `claim as new `and desire to secure by Letters Patent is:

1. In a combined furnace and stokerthe combination of a re box having arotatable grate, a motor, intermittently operated motor starting andstopping mechanism including a circuit breaker in electrical connectionwith said motor,

means driven by said motor and including intermittently operated drivingconnections to lintermittently rotate said grate, a stationary partitionextending upwardly and above said grate in a direction radial withrespect thereto, said partition functioning to sweep ashes from thegrate whereby to provide a clear space on the grate to receive fuel, afuel delivery conduit having one side wall approximately aligned withsaid partition and forming the support for said partition, the fueldelivery conduit having 'a throat opening to said fire box, a ram insaid fuel delivery conduit for charging fuel upon said grate in adirection approximately radial thereto, and a driving connection betweensaid ram and motor for intermittently reciprocating said ram in timedrelation to the rotatory movement of the grate.

2. In a combined furnace and stoker, the combination of a fire boxhaving a rotatable gratea motor drive-n intermittently rotatedcrankshaft having la crank, drive gearing between said shaft and grateincluding an intermittently operate-d driving connection, a fueldelivery conduit having one side wall extending radially with respect tothe grate and having a throat opening to the firey box above the grate,an ash sweeping partition extending upwardly and above the grate,secured to and supported by said side wall and forming a continuation ofsaid side wall, a ram reciprocating in said fuel delivery conduit, and aconnection betweensaid ram and crank of the crank shaft arranged to movethe ram toward the grate when the latter is stationary.

3. Ina combined furnace and stoker, the combination of a ire box havinga rotatable grate, a

partition extending upwardly and above said grate for sweeping ashestherefrom, whereby to provide a clear space on the grate to receive fuelthereon, a motor driven intermittently rotated crank shaft having acrank, drive gearing between said shaft and grate including anintermittently operated driving connection, a fuel delivery conduithaving one side wall extending radially with respect to the grate andforming the support for s'aid partition, said fuel delivery conduithaving a throat opening to the fire box above the grate adjacent saidpartition, a ram reciprocating in said fuel delivery conduit, .and aconnection between said ram and the crank of the crank shaft for movingthe ram toward the grate while the latter is stationary.

4. In a combined furnace and Stoker, the combination of a re box havinga rotatable grate, a motor driven intermittently rotatedr crank shafthaving a crank, a `beveled gear wheel supporting said grate, a bearingfor said beveled gear wheel,r

`an intermittently rotated Shaft having a beveled pinion thereon meshingwith said gear wheel, drive gearing between said crank shaft and in1termittently rotated shaft including an intermittently operated drivingconnection, a fuel delivery conduit having one side wall extendingradially with respect to the grate and having a throat opening to thefire box above `the grate, an ash sweeping partition extending upwardlyand above said grate substantially in line with said side wall, andbeing supported by said side wall, a ram reciprocating in said fueldelivery conduit, and a connection between said ram and the crank of thecrank shaft for moving the ram toward the grate while the latter isstationary.

5. In a combined furnace and Stoker, the combination of a fire boxhaving a rotatable grate, a motor driven intermittently rotated crankshaft having a crank, a beveled gear Wheel supporting said grate, abearing for said beveled gear wheel, an intermittently rotated shafthaving a beveled pinion thereon meshing with said beveled gear wheel, apair of intermeshing gear wheels, one of which is a mutilated gearwheel, a beveled gear wheel connected to the driven one of said gearwheels, a beveled pinion on said intermittently rotated shaft meshingwith said last mentioned beveled gear wheel, a fuel delivery conduithaving one side wall extending radially with respect to the grate andhaving a throat opening to the nre vbox above the grate, a ramreciprocating in said fuel delivery conduit, and a connection betweensaid ram and the Acrank of the crank shaft for moving the ram toward thegrate while the same is stationary.

6. In a combined furnace and Stoker, the combination of a re box havinga rotatable grate, a trap door pfivotally carried by said grate, anannular track upon which said trap door rides, said track having adownwardly offset portion therein permitting the trap door to drop,motor driven means to intermittently rotate said grate, a stationarypartition extending upwardly and above said grate in a direction radialwith respect thereto, a fuel delivery conduit having one side wallsubstantially aligned with said partition and having a throat opening tosaid re box, said side wall forming the support for the partition, a ramin said fuel delivery conduit for charging fuel upon said grate in adirection approximately radial thereto, and a connection to said ram andmotor driven means for itnermitl'ently reciprocating said ram in timedrelation to the move ments of the grate.

7. In a combined furnace and Stoker, the comn bination of a furnacebody, a smoke pipe leading therefrom, a damper in said Smoke pipe, a rebox having a rotatable grate, a motor, driving means driven by saidmotor to rotate the grate, a fuel delivery conduit having a throatopening to the re box, a ram in said fuel delivery conduit, a connectionbetween said ram and driving means, electrical time control means forstarting and stopping the motor, at definite intervals, and manuallyoperable time setting means for `Changing the lengths of intervals forstarting the motor, a member of said time control means having exibleconnecting means connected to said damper, whereby the setting of thetime control means varies the position of the damper.

8. In a combined furnace and Stoker, `the combination of a furnace body,a smoke pipe leading therefrom, a nre box having a rotatable grate,

a motor, means driven by said motor to rotate the grate, a fuel deliveryconduit having a throat openingto the fire box, a ram in said fueldelivery conduit, a connection between said ram and motor driven means,a damper in said smoke pipe, electrical time control means for startingand stopping the motor and actuating said damper, comprising a motordriven disc hav ing annular rows of contacts, an adjustable con tactcarrying member having contact fingers for making contact with thecontacts of the several rows, said contact fingers comprising terminalsin an electric circuit to the motor, operative connections between saidcontact carrying member and damper, and means to adjust said contactcarrying member including an indicating dial.

9. In a combined furnace and Stoker, the combination of a furnace body,a smoke pipe leading therefrom, a re box having a rotatable grate, amotor, means driven by said motor to rotate the grate, a fuel deliveryconduit having a throat opening to the fire box, a ram in said fueldelivery conduit, a connection between said ram and motor driven means,electrical time control means for starting and stopping the motor, adamper located in said smoke pipe, and means actuated by said controlmeans for actuating said damper.

GEORGE H. CUSHING.

